Sending mail and updating

I am a new user to the program and am finding it a bit complicated. Why, when I attempt to send email, I get the following message "553 Sorry, that domain isn't in my list of allowed rcpthosts" and it doesn't send the email. How, also, do you upgrade/update to new versions? Do you have to download the new version and install it? thanks for the help.

I think to help we would need a little more information like what type of server you are connecting to, eg Zimbra, Yahoo! etc.

In general terms the error would suggest either a problem with the server you are connecting to and/or the address you are sending to. It would help to know whether it is all email addresses, only one address or domain.

As to upgrades: Upgrades for ZD1 were prompted and scripted to run automatically. I understand that ZD2 is intended to behave similarly when released but it is unlikely to happen upgrading from ZD1 to ZD2 - that will probably be a manual new install.